This invention is based on Disclosure Document No 474944, filed May 30, 2000.
This invention is directed to raising and lowering objects, in particular, objects such as theater scenic elements, suspended from fly sets, by failsafe motorized means.
Most of the present-day fly systems in theaters are manually operated counterweight sets. Each counterweight set consists essentially of one pipe batten, somewhat longer than the width of the proscenium opening, suspended by lines or cables, such as wire ropes, which are spaced approximately 8-10 ft apart along its length. Each wire rope passes from the suspended pipe batten over a sheave or loftblock, which is either mounted on the stage gridiron or underhung from the stagehouse roof beam. From the loftblocks all lines lead to a common headblock, mounted at one side of the stage and pass over it down to a counterweight arbor. The counterweight arbor is typically a steel frame, supporting lead, cast iron or steel weights. Counterweight arbors are guided by tee tracks, mounted on the stage side wall.
An operating rope is tied to the top of each counterweight arbor. From there it goes up and over the headblock, then down and around a rope tension sheave, (which is located below the counterweight usually at stage floor height) and up again where it is connected to the bottom of the counterweight arbor. The operating rope also passes through a friction type rope lock, which holds the nearly balanced pipe batten and counterweight arbor in position. The pipe battens are usually spaced six inches on center, parallel to the proscenium opening, and are sometimes spaced even closer. Wider spacing is used in smaller theaters. The number of fly sets in theaters varies. A small high school theater may have only 20-25, whereas more than 100 may be used in large theaters.
These known systems have disadvantages. Loading and unloading counterweights for balancing the loads suspended by the pipe battens is time consuming and dangerous. The loading and unloading of weights usually happens when the batten is at stage level and the counterweight arbor is at gridiron level. There have been numerous accidents when counterweights were dropped from 60-70 feet above the stage onto people standing below operating other counterweight sets. In case of unbalance, the pipe batten and counterweight may run away when the rope lock is opened.
While some motorized winches have been used in larger theaters, they are expensive and often not affordable for smaller theaters.
An object of the present invention is a motorized failsafe fly system winch that can be substituted for the manually operated counterweight set Anther object of the present invention is a motorized failsafe fly system winch that is compact and can be economically manufactured.
A further object of the present invention is a motorized failsafe fly system winch which does not require counterweights and which permits elimination and simplification of several parts, normally used for similar winches, without sacrificing the functioning.
Yet another object of the invention is a movable winch drum and carriage combination for raising and lowering theatre scenery which incorporates functions for emergency braking, for moving the drum (and its support base) in synchronization with relation to the carriage and for driving of a limit switch if desired.
A still further object of the present invention is a motorized failsafe fly system winch which is compact and sufficiently versatile that it can easily be adapted for mounting along the theatre side walls or to a gridiron or to the ceiling.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described the preferred embodiments of the invention, and in which like reference numerals denote the same or similar components.